Modular Downhole Junk Basket Assembly

ABSTRACT

A modular junk basket assembly adapted for attachment to a wellbore tubing string comprises a tubular body having a plurality of debris ports that feed into an integrally formed basket space. A baffle is slidably mounted on the tubular body which translates along the length of the tubular body to a position behind the debris ports, relative to the fluid pressure created on the baffle. The baffle has a plurality of fluid passageways which allow passage of drilling fluid and small debris as larger debris is diverted toward the debris ports and into the debris basket.

PRIORITY

This application claims priority to U.S. provisional application Ser. No. 62/094,776 filed Dec. 12, 2014 entitled “Modular Downhole Junk Basket Assembly”, the entire content of which is incorporated by reference.

FIELD OF THE INVENTION

This invention relates to an oilfield tool and more particularly to a modular downhole collection basket with an articulable baffle to deflect debris into a debris basket opening.

BACKGROUND OF THE INVENTION

Various types of debris or junk basket assemblies have been devised for collecting drilling fluid debris such as mud cake, cement and cement cake, and metal and plastic fragments from a wellbore during a cleaning operation. The conventional junk basket assembly has a debris basket dimensioned to collect debris flowing around and external to the debris basket. The top end of the debris basket is open and relies on free falling debris in the upward flowing drilling fluid to fall into the opening of the debris basket where it remains until the debris basket is removed. However, the force of the upward-flowing drilling fluid carrying the debris can divert a substantial portion of the debris away from the basket impeding the collection of the drilling fluid debris in the debris basket. This is problem particularly occurs when fluid circulates through the debris basket and upward through an annulus in the well as the basket is retrieved to the surface. Other debris baskets have complicated designs with multiple components making them expensive to build.

FIG. 1 illustrates a conventional junk basket assembly 1 having a central mandrel 2 and a debris basket 4 attached between upper and lower segments of a tubing string 6 that is positioned in a wellbore 7 having a casing liner 3. When a tubing string 6 is so positioned, an annular space 8 creates a flow area in the wellbore 7 between the casing 3 and the tubing string 6 and basket debris 4. The flow area in the wellbore 7 in annular space 8 is decreased at the debris basket 4 because debris basket 4 has a diameter greater than that of the central mandrel 2 and the attached tubing string 6. During well operations, fluid F is pumped downward through the tubing string 6 and upward through the casing 3 in the wellbore flow area created by annular space 8 that creates a circulation of fluid F toward the surface of wellbore 7.

During this circulation of fluid F in wellbore 7, fluid F has a first velocity as it circulates through wellbore flow area A in annular space 8. When Fluid F flows upward in the annular space 8 through wellbore flow area B at debris basket 4, fluid F has a second velocity that is greater than the first velocity in wellbore flow area A because flow area A of annular space 8 is decreased between the casing 3 and the debris basket 4. As fluid F continues to flow upward in wellbore 7 toward the surface, annular space 8 abruptly widens directly above the debris basket 4. This widening of annular space 8 creates an increased flow area C in annular space 8 so that the velocity of fluid F in flow area C decreases to a third velocity that is less than the second fluid velocity created in flow area B.

The decrease in fluid velocity from flow area B to flow area C creates eddy currents that divert a portion of the fluid F entering flow area C from flow area B toward central mandrel 2 above the opening 4 a of debris basket 4 into flow area E of annular space 8. The fluid diverted into flow area d se c into flow area E and into opening 4 a of debris basket 4 so that debris carried by that portion of fluid F is captured and collected in debris basket 4. However, simultaneously, a portion of the fluid F entering flow area C from flow area B will flow upward in annular space 8 into flow area D and will remain uncaptured as the fluid F flow upward to the wellbore surface. Thus, at least some of the flow of fluid F in annular space 8 is diverted away from the debris basket 4 of conventional a junk basket assembly and the collection of debris in fluid F by debris basket 4 is impeded.

From the foregoing it can be seen that there is a continuing need for a junk basket assembly that will reduce fluid diversion away from the debris basket as fluid flows toward the surface of the wellbore and that will increase the rate of wellbore debris collection during cleaning operations.

SUMMARY OF THE INVENTION

The present invention provides a tubular modular junk basket assembly adapted for attachment to a tubing string used in a wellbore for collection of drilling fluid debris to satisfy the aforementioned needs. The modular junk basket assembly has a central tubular mandrel or tool body, an integrated debris collection basket operable to collect debris from the wellbore drilling fluid, and a slidably translatable baffle operable to deflect and divert fluid and debris flowing in the wellbore annulus around the debris basket assembly into the debris collection basket. The integrated debris collection basket has a plurality of debris ports distributed radially about the peripheral radial surface of the tubular tool body. The slidably translatable baffle has a plurality of fluid passages to allowing fluid flow through the baffle as the junk basket assembly is moved into and out of a wellbore. Fluid pressure against the translatable baffle created as fluid flows around the junk basket assembly slides the baffle along the tool body to a desired position adjacent the debris ports in the direction of fluid flow to deflect and divert debris of a desired size through the debris ports and into the debris collection basket while allowing fluid and debris of a lessor size to pass through the baffle fluid passages and circulate in the wellbore.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a conventional junk basket assembly.

FIG. 2 is a partial cross-section longitudinal view of the modular junk basket assembly of Applicant's invention on a tubing string inserted into a wellbore where fluid is flowing upward in the wellbore annulus.

FIG. 3 is a partial cross-section longitudinal view of the modular junk basket assembly of Applicant's invention on a tubing string inserted into a wellbore where fluid is flowing downward in the wellbore annulus.

FIG. 4 is an isometric view of the modular junk basket assembly shown in FIG. 2 with the baffle translated to facilitate diversion and capture of drilling fluid debris during its insertion into a wellbore.

FIG. 5 is an isometric view of the modular junk basket assembly shown in FIG. 2 with the baffle translated to facilitate diversion and capture of drilling fluid debris during it withdrawal from a wellbore.

FIG. 6 is an end view of an embodiment of the translatable baffle having a plurality of U-shaped fluid passageways.

FIG. 7 is an end view of an alternate embodiment of the translatable baffle having a plurality of circular fluid passageways.

FIG. 7A is a cross-section view of the baffle of FIG. 7 cut along line C-C showing the angle baffle face.

FIG. 8 is an end view of still another alternate embodiment of the translatable baffle.

FIG. 8A is a cross-section view of the baffle of FIG. 7 cut along line D-D showing the annulus gap between the baffle and the wellbore casing.

FIG. 9 is a longitudinal cross-sectional view of an alternate embodiment of the modular junk basket assembly shown in FIG. 2.

FIG. 10 is an enlarged partial longitudinal cross-sectional view of the modular junk basket assembly shown in FIG. 9.

FIG. 11 is an end view of the translatable baffle of FIG. 9.

FIG. 12 and FIG. 12A are detail views of linear slides for orientation and translation of the translatable baffles shown in FIG. 9.

FIG. 13 is a partial isometric view of the translatable baffle of FIG. 9 showing the offset orientation of the high-flow baffles with the translatable baffles abutting to close a fluid flow path through the baffle gaps during low pressure conditions.

FIG. 14 is a partial isometric view of the translatable baffle of FIG. 9 showing the offset orientation of the high-flow baffles with the translatable baffles separated to create a fluid flow path through the baffle gaps during high pressure conditions.

FIG. 15 is a partial longitudinal cross-section view of the junk basket assembly shown in FIG. 9 in a wellbore having upward fluid flow in the annular space, the baffles separated by increased fluid pressure on the baffles.

FIG. 16 is a partial longitudinal cross-section view of the junk basket assembly shown in FIG. 9 in a wellbore having downward fluid flow in the annular space, the baffles separated by wellbore debris to create increased fluid pressure on the baffles.

FIG. 17 is a partial longitudinal cross-section of an alternate embodiment of the junk basket assembly shown in FIG. 9.

DETAILED DESCRIPTION

FIGS. 2 and 3 show partial longitudinal cross-sectional views of the upper half of the modular junk basket assembly 10 of applicant's invention. The junk basket assembly 10 and its components are symmetrically oriented about the longitudinal centerline CL junk basket assembly 10. As shown in FIGS. 2 and 3, the modular junk basket assembly 10 is comprised of a longitudinally oriented central tubular mandrel or tool body 100, an integrated debris collection basket 40 operable to collect debris from wellbore drilling fluid, and a ring-shaped baffle 50 slidably mounted and translatable operable to deflect and divert fluid and debris flowing in a wellbore in both an upward or a downward direction.

Tool body 100 of junk basket assembly 10 has an upper end connection 20 configured for threadable attachment to an upper tubing string 15, a lower end connection 26 configured for threadable attachment to a lower tubing string 17, and a central through-bore 22 in communication with the through-bore in the upper tubing string 15 and the lower tubing string 17. The upper tubing string 15 and lower tubing string 17 with the attached basket assembly 10 are positioned in a wellbore 12 having an interior surface 14 such as the interior surface of a casing string 16.

The casing string 16 may be in fluid communication with a hydrocarbon formation. The modular junk basket assembly 10 may be of any suitable diameter to fit within the interior surfaces 14 of casing string 16 while creating an annular space 42 in the wellbore 12 between the casing string 16 and the tool assembly 10 and the upper and lower tubing strings 15 and 17 through which debris and drilling fluid F may pass.

The assembly 10 is comprised of a longitudinally extending tubular mandrel creating tubular tool body 100. Tubular tool body 100 has an integrally formed longitudinally extending debris collection basket 40 with an upper basket end 41 and a lower basket end 43. Debris collection basket 40 has a cover 19 with a plurality of debris ports 18 distributed radially about the cover 19 in proximity to the upper basket end 41 and a plurality of fluid drain holes 45 distributed radially about the cover 19 in proximity to the basket lower end 43. The debris ports 18 and drain holes 45 provide fluid communication between debris collection basket 40 and the annular space 42. The drain holes 45 provide a means for draining drilling fluid and small debris from the collection basket 40 as debris laden fluid is delivered into the basket 40 through debris ports 18.

A translatable ring-shaped baffle 50 is slidably mounted around the tool body 100 so that the ring-shaped baffle 50 is slidably translatable longitudinally along the tool body 100 across the debris ports 18 of the basket 40 between a first radial shoulder 56 a constructed around the tool body 100 adjacent to the upper end of the collection ports 18 and an opposing second radial shoulder 56 b constructed around the tool body 100 adjacent to the lower end of the collection ports 18 as shown in FIGS. 4 and 5. The ring-shaped baffle 50 has a circular profile providing a 3600 baffle surface around the entire periphery of tool body 100.

Cover 19 of the debris collection basket 40 may be fabricated as a separate tubular and welded or otherwise attached to the tool body 100 or it may be integrally formed as part of the tool body 100. Because tool body 100 holds the weight of the lower tubing string 17 and transfers the torque from the upper tubing string 15 to the lower tubing string 17, it must be sized and constructed of material having sufficient strength to withstand the tensile and torsional forces being created. Preferably the tool body 100 and cover 19 are constructed and arranged as a single unitary structure to eliminate multiple parts which are subject to failure during operation. In one configuration, only the tool body 100 is made of high strength steel. The baffle 50 may be manufactured from steel or other material having a lessor yield strength as it need only to withstand forces created from drilling fluid pressure and wellbore debris and obstructions and not the torque and weight imposed by the upper and lower tubing strings.

A plurality of centralizers 46 are positioned about tool body 100 to keep the assembly 10 centralized within the casing string 16. When installed between the upper tubing string 15 and the lower tubing string 17 and inserted into wellbore 12, junk basket assembly 10 substantially tracks the inner surface 14 of casing string 16. The centralizers 46 are configured to slidably abut the interior surface 14 of casing string 16 to maintain the centralized position of assembly 10 and minimize the risk of frictional or collision damage to the baffle 50 and the tool body 100 caused by contact with the casing string 16. The baffle 50 is configured to have a diameter less than the drift diameter of the tool body and centralizers 46.

Now referring to FIGS. 4 and 5, the translatable baffle 50 is slidably positioned about tool body 100 so that the translatable baffle 50 is allowed to translate, i.e. drift or slide, longitudinally along the tool body 100 across debris ports 18 between upper radial shoulder 56 a and lower radial shoulder 56 b of the debris collection basket 40. Shoulders 56 a and 56 b stop baffle 50 in a desired position adjacent the edge of debris ports 18 when baffle 50 translates across the debris ports 18. The baffle 50 has front and rear radially extending wall surfaces 51 having a plurality of radially spaced fluid passages shown as fluid slots 52. The force created from the pressure of fluid F on the radially extending wall surface 51 and drag forces created as fluid F flows through fluid slots 52 will alternately slidably translate baffle 50 between radial shoulder 56 a and radial shoulder 56 b across the debris port 18 depending upon the direction of fluid flow.

FIG. 4 shows the fluid F moving upward with the slidably translatable baffle 50 moved toward the upper end 20 of the tool body 100 past debris port 18 over the debris collection basket 40 to abut upper radial shoulder 56 a. FIG. 5 shows the fluid F moving downward with the slidably translatable baffle 50 moved toward the lower end 26 of tool body 100 past debris port 18 over the debris collection basket 40 to abut lower radial shoulder 56 b. When debris in fluid F encounters baffle 50 debris contacting wall 51 will be diverted toward debris ports 18 for capture in debris collection basket 40. Baffle 50 also has a plurality of flow passages shown as flow slots 52 which allow wellbore fluid carrying small debris such as drill cuttings, drilling mud, plastic and metal to pass while trapping larger matter carried in fluid F which is then diverted toward debris ports 18 and into basket space 40.

Now referring to FIG. 6 and FIG. 7, the walls 51 of ring-shaped baffle 50 may be configured with a plurality of flow slots 52 of a desired size to provide a passage for debris particles through the baffle 50. The flow slots 52, as shown in FIG. 6, may be U-shaped slots spaced radially around the outer peripheral edge of baffle 50. The flow slots 52 may also be round holes through the baffle walls 51 as shown in FIG. 7. The flow slots 52 may also be configured in any desired size or shape thought required to allow passage of drilling fluid and particulate matter of a desired size across or through baffle 50.

As shown in FIG. 7A, wall 51 of baffle 50 may be shaped to have an inward slope or angle α to encourage fluid debris to be diverted to flow downward toward debris port 18 into the debris collection basket 40. When subjected to fluid pressures, baffle 50 with inwardly sloped or angled wall 21 will deflect larger particulate matter and debris into the adjacent debris ports 18 around the entire outer periphery of tool body 100. Baffle 50 has a diameter DD equal to or less than the drift diameter of the tool body 100 and centralizers 46

Referring to FIGS. 8 and 8A, baffle 50 may be configured without flow slots 52. In this configuration baffle 50 may be sized to have a diameter DD that creates a desired annular space 42 between the interior surface 14 of casing string 16 and the outer radial edge 53 of baffle 50 to provide a desired fluid passage for wellbore fluid F and particulate matter of a desired size around baffle 50 to travel around the baffle 50 while larger particulates and debris are retained by the baffle 50.

FIGS. 9 and 10 show an alternate embodiment of the junk basket assembly 10, designated as 10A, that is configured for high fluid flow conditions. As shown in FIG. 10, a detail view of area G shown in FIG. 9, junk basket assembly 10A has first and second high-flow baffles 150, comprising an upper high-flow baffle 150 and a lower ring-shaped high-flow baffle 150, that are releasably restrained and held in position by shear pins or shear screws 30 that are designed to shear when subjected to a predetermined shear force. The upper and lower high-flow baffles 150 are slideably mounted around tool body 100 and sandwich a radial retaining structure 35, such as a plurality of spaced apart retaining studs or a retaining ring that encircles the radial outer periphery of tool body 100. The retaining structure 35 is positioned between radial shoulders 56 a and 56 b at a desired position adjacent the edge of debris ports 18.

As shown in FIG. 11, each high-flow baffle 150, has a plurality of flow slots 52 sized to create a desired wellbore fluid flow channel. The flow slots 52 in each high-flow baffle 150 may be configured in any desired size or shape, including round, oval, or U-shaped as shown in FIG. 6, as thought required to allow passage of drilling fluid and particulate matter of a desired size across or through high-flow baffle 150. In addition to the flow slots 52, each high-flow baffle 150 has a plurality of flow gaps 153 equally spaced around the outer radial periphery of the baffle wall 151. The flow gaps 153 are also sized to a plurality of fluid flow spaces 154 across each high-flow baffle 150. The diameter DD of high-flow baffle 150 is sized to create a desired annular space 42 between the interior surface 14 of casing string 16 and the outer radial edge 53 of the high-flow baffles 150 as shown in FIG. 10.

Each high-flow baffle 150 is slidably mounted around tool body 100 to slidably translate longitudinally along said tool body 100 on a plurality of linear slides 31. The linear slides 31 may be grooves or slots 32 that correspond with longitudinally extending slide rails 33 spaced radially around the outer peripheral surface of the tool body 100 as shown in FIG. 12. The linear slides 31 may also be comprised of grooves or slots 32 that correspond with a plurality of keys 37 such as pins, bolt heads, screws or the like in lieu of slide rails 33 as shown in FIG. 12A. The grooves or slots 32 of the linear slides are also utilized to orient the position of the flow gaps 153 of the high-flow baffles 150 on the tool body 100.

When assembled as shown in FIGS. 9 and 10, the upper and lower high-flow baffles 150 of junk basket assembly 10A are oriented on the body 100 by the orientation slots so that the flow gaps 153 on the adjacent upper and lower high-flow baffles 150 are staggered or offset and not aligned as shown in FIG. 13. Staggering the flow gaps 153 in the adjoining upper and lower high-flow baffles 150 will close the flow gaps 153 and the flow space 154 in the high-flow baffles 150 and leave only the annular space 42 and the flow slots 52 as flow channels for wellbore fluid. The annular space 42 and the flow slots 52 provide a fluid passage for wellbore fluid F and particulate matter of a predetermined desired size carried in the fluid F around and through the high-flow baffles 150 while debris and particulate matter in the wellbore fluid F that is greater than that desired is retained by the high-flow baffles 150.

When junk basket assembly 10A is in use in high-flow conditions, the staggered high-flow baffles 150 will divert debris carried by the wellbore fluid F into the collection basket 40 of the assembly 10A. If basket 40 fills with debris, such that uncollected debris will clog the flow space provided by annular space 42 and the flow slots 52 of the high-flow baffles 150, and the force generated by fluid F against the clogged baffles 150 reaches a predetermined force, the screws 30 releasably holding the upper high-flow baffle 150 in place against retaining ring 53 adjacent the lower high-flow baffle 150 will shear or sever. The severed shear screws 30 releases the upper high-flow baffle 150 allowing it to slidably translate longitudinally on slides 131 along tool body 100 and separate from lower high-flow baffle 150 which will be restrained from translation by retaining structure 35.

The separation of upper and lower high-flow baffles 150 opens flow spaces 154 and creates a flow path 155 for fluid F through the flow gaps 153 of the upper and lower high-flow baffles 150 as shown in FIG. 14. When the high-flow baffles 150 are so separated to create the fluid flow path 155, fluid F and any carried large and small debris will pass unobstructed through the flow spaces 154 of flow gaps 153 on the upper and lower high-flow baffles 150. Fluid F flowing through fluid flow path 155 created by the separation of the high-flow baffles 150 and will serve to clear any clogging of the annular space 42 and the flow slots 52 of the high-flow baffles 150.

FIG. 15 shows a partial longitudinal cross-section view of the junk basket assembly 10A in a wellbore having upward fluid flow in the annular space 42 with the slots 52 of the high-flow baffles 150 clogged by wellbore debris to create increased fluid pressure on the high-flow baffles 150. Lower high-flow baffle 150 is held in place by retaining structure 35. The increased fluid pressure on the upper high-flow baffle 150 has severed the shear screws 30 releaseably holding upper high-flow baffle 150 against retaining structure 35 adjacent lower high-flow baffle 150 allowing upper high-flow baffle 150 to separate from lower high-flow baffle 150 and slidably translate along liner slides 31 toward upper shoulder 56 a where the upper high-flow baffle 150 is retained. With the upper high-flow baffle 150 separated from the lower high-flow baffle 150, the flow spaces 154 across flow gaps 153 on the high-flow baffles 150 are opened to create flow path 155 for fluid F between the upper and lower baffles 150 as shown in FIG. 14.

FIG. 16 shows a partial longitudinal cross-section view of the junk basket assembly 10A in a wellbore having downward fluid flow in the annular space 42 with the slots 52 of the high-flow baffles 150 clogged by wellbore debris to create increased fluid pressure on the high-flow baffles 150. The fluid increased pressure on lower high-flow baffle 150 has severed the shear screws 30 releasably holding lower baffle 150 against retaining structure 35 adjacent upper baffle 150. Upper high-flow baffle 150 is held by retaining structure 35 as lower high-flow baffle 150 is separated from upper baffle 150 to slidably translate along linear slides 31 across debris ports 18 toward lower shoulder 56 b where it is retained. The separation of the upper and lower high-flow baffles 150 opens the flow spaces 154 across the flow gaps 153 on the staggered upper and lower high-flow baffles 150 and a flow path 155 for fluid F is created across the flow gaps 153 between the upper and lower baffles 150 in a manner similar to that shown in FIG. 14.

FIG. 17 shows a partial longitudinal cross-section of junk basket assembly 10B, an alternate embodiment of the junk basket assembly 10A shown in FIG. 9. In junk basket assembly 10B shown in FIG. 17, a plurality of longitudinally oriented compression springs 58 a and a plurality of longitudinally oriented compression springs 58 b are spaced radially around the outer periphery of the tool body 100 and are provided in lieu of shear screws 30. Compression springs 58 a provide a spring force against upper high-flow baffle 150 and compression springs 58 b provide a spring force against lower high-flow baffles 150 to releasably restrain and hold the upper and lower high-flow baffles 150 against retaining structure 35. During tool operation, when the fluid pressure force on the upper and lower high-flow baffles 150 is less than the compression force exerted by compression springs 58 a or by compression springs 58 b, the upper and lower high-flow baffles 150 will be restrained from translation and remain adjacent to each other against retaining structure 35.

When one of the high-flow baffles 150 becomes clogged and the fluid pressure on the clogged high-flow baffle 150 increases above the compression force exerted by corresponding springs 58 a or 58 b so that the clogged baffle 150 is no longer restrained and held in position against retaining structure 35 by the compression springs 58 a or 58 b, the clogged high-flow baffle 150, whether upper or lower high-flow baffle 150, will separate and slide along liner slides 31 to open the flow spaces 154 across the flow gaps 153 of the upper and lower high-flow baffles 150 to create flow path 155 for fluid F between the upper and lower high-flow baffles 150 in the manner shown in FIG. 14. The flow of fluid through the flow gaps 153 serves to remove debris clogging the high-flow baffles 150 which will reduce the fluid pressure force on the then unclogged high-flow baffle 150. When the fluid pressure force on the unclogged high-flow baffles 150 is less than the compression force exerted on the high-flow baffles 150 by springs 58 a and 58 b, the high-flow baffle 150 will slide back along liner slides 31 toward an adjacent alignment of the upper and lower high-flow baffles against retaining structure 35 and as a result close the flow spaces 154 across the flow gaps 153 and the flow path 155 for fluid F.

Each spring 58 a and 58 b may be positioned around a guide rod 59 that extends longitudinally along the body 100. The guide rods 59 may also serve as the linear slides 31 used for orientation of the upper and lower baffles 150.

Changes may be made in the form, construction and arrangement of the parts of the junk basket assembly described herein without departing from the spirit and scope of the invention or sacrificing any of the invention's material advantages. The description and drawings provide only exemplary embodiments and the invention can be practiced by other than the described embodiments, which are presented only for illustration and not limitation. 

We claim:
 1. A modular junk basket assembly comprising: (a) a longitudinally extending tubular tool body having a central through-bore, an upper end, and a lower end; (b) a debris basket within said tool body; (c) a plurality of radially distributed debris ports in communication with said debris basket; and (d) a ring-shaped baffle slidably mounted around said longitudinally extending tool body, said baffle slidably translatable along said longitudinally extending tool body across said plurality of debris ports.
 2. The modular junk basket assembly recited in claim 1, wherein said debris ports are positioned between a first shoulder positioned at the periphery of said tool body and a second shoulder positioned at the periphery of said tool body whereby said baffle is slidably translatable between said first and second shoulders.
 3. The modular junk basket assembly recited in claim 2, wherein said baffle has a plurality of flow slots.
 4. The modular junk basket assembly recited in claim 3, wherein said flow slots are radially spaced around the periphery of said baffle.
 5. The modular junk basket assembly recited in claim 3, wherein said flow slots are holes through said baffle.
 6. The modular junk basket assembly recited in claim 4, wherein said flow slots are U-shaped.
 7. The modular junk basket assembly recited in claim 3, wherein said baffle has an inwardly angled wall.
 8. A modular junk basket assembly comprising: (a) a longitudinally extending tubular tool body having a central through-bore, an upper end, and a lower end; (b) a debris basket within said tool body; (c) a plurality of radially distributed debris ports in communication with said debris basket; (d) a first shoulder on the periphery of said tool body; (e) a second shoulder on the periphery of said tool body; (f) a retaining structure at the periphery of said tool body positioned between said first shoulder and said second shoulder; and (g) a first ring-shaped baffle slidably mounted around said longitudinally extending tool body and a second ring-shaped baffle slidably mounted around said longitudinally extending tool body, said first and second baffles releasably restrained against said retaining structure.
 9. The modular junk basket assembly recited in claim 8, wherein said first and second baffles have a plurality of equally spaced flow gaps along the radial periphery of said baffles, said flow gaps providing a plurality of fluid flow space across each of said first and second baffles.
 10. The modular junk basket assembly recited in claim 9, wherein said first and said second ring-shaped baffles are oriented on said tool body to stagger said flow gaps and close said fluid flow space across each of said first and second baffles.
 11. The modular junk basket assembly recited in claim 10, wherein said first and second baffles are slideably retained on linear slides.
 12. The modular junk basket assembly recited in claim 11, wherein said first and second baffles are releasably restrained by shear screws or by shear pins.
 13. The modular junk basket assembly recited in claim 11, wherein said first and second baffles are releasably restrained by compression springs.
 14. A method of removing debris from fluid in a wellbore, comprising the steps of: (a) providing a junk basket assembly comprising: (i) a longitudinally extending tubular tool body having a central through-bore, an upper end, and a lower end; (ii) a debris basket within said tool body; (iii) a plurality of radially distributed debris ports in communication with said debris basket; and (iv) a ring-shaped baffle slidably mounted around said longitudinally extending tool body, said baffle slidably translatable along said longitudinally extending tool body across said plurality of debris ports; (b) attaching said junk basket assembly to a tubing string; (c) inserting said tubing string with said attached junk basket assembly into a wellbore thereby creating a annular space for wellbore fluid between said wellbore and said junk basket assembly; and (d) providing an upward flow of wellbore fluid in said annular space, said wellbore fluid carrying wellbore debris, whereby fluid pressure on said baffle slides said baffle to a position upward from said fluid ports thereby diverting at least some of said debris in said wellbore fluid through said plurality of debris ports and into said debris basket.
 15. The method of claim 14, further comprising the step of providing a downward flow of wellbore fluid in said annular space, said wellbore fluid carrying wellbore debris, whereby fluid pressure on said baffle slides said baffle to a position downward from said fluid ports thereby diverting at least some of said debris in said wellbore fluid through said plurality of debris ports and into said debris basket.
 16. The method as recited in claim 15 further comprising the step of providing said baffle with a plurality of flow slots, said flow slots allowing said wellbore fluid and a least some wellbore debris to flow through said slots.
 17. A method of removing debris from fluid in a wellbore, comprising the steps of: (a) providing a junk basket assembly comprising: (i) a longitudinally extending tubular tool body having a central through-bore, an upper end, and a lower end; (ii) a debris basket located within said tool body; (iii) a plurality of radially distributed debris ports in communication with said debris basket; (iv) a first shoulder extending radially around the periphery of said tool body; (v) a second shoulder extending radially around the periphery of said tool body; (vi) a first releasably restrained ring-shaped baffle slidably mounted around said longitudinally extending tool body and a second releasably restrained ring-shaped baffle slidably mounted around said longitudinally extending tool body; and (vii) a retaining structure between said first shoulder and said second shoulder, said retaining structure sandwiched by said first and said second releasably restrained baffles; (b) attaching said junk basket assembly to a tubing string; (c) inserting said tubing string with said attached junk basket assembly into a wellbore thereby creating a annular space for wellbore fluid between said wellbore and said junk basket assembly; (d) providing an upward flow of wellbore fluid in said annular space, said wellbore fluid carrying wellbore debris, whereby at least a portion of said wellbore debris is diverted by said first and second baffles into said debris basket; and (e) wherein when fluid pressure of said upward flow of wellbore fluid on said first and second baffles reaches a predetermined pressure force, said releasably restrained first baffle is released to slidably translate away from said second baffle thereby creating a flow space between said first baffle and said second baffle.
 18. The method of claim 17, further comprising the step of providing a downward flow of wellbore fluid in said annular space, said wellbore fluid carrying wellbore debris, said wellbore fluid carrying wellbore debris, whereby at least a portion of said wellbore debris is diverted by said first and second baffles into said debris basket, wherein when fluid pressure on said first and second baffles reaches a predetermined pressure force, said releasably restrained second baffle is released to slidably translate away from said first baffle thereby creating a flow space between said first baffle and said second baffle.
 19. The method of claim 18 wherein said first ring-shaped baffle and said second ring-shaped baffle have a plurality of flow gaps.
 20. The method as recited in claim 19 wherein said first ring-shaped baffle and said second ring-shaped baffle are oriented on said tool body whereby said flow gaps of said first and said second baffles are closed. 